Rangelands are widely distributed and occupy a large portion of the world's available land. Estimated global land area of rangelands varies widely from as little as 30% to nearly 70% based on the definition of rangelands. Nonetheless, rangelands provide many ecosystem services to human populations around the world. They support almost one-third of the global human population, store about half of the global terrestrial carbon, support 50% of the world's livestock, and contain over one-third of the biodiversity hot spots. The monitoring and assessment of rangelands is thus of great interest. Increasingly, however, the ability of rangelands to continue providing these services is challenged by anthropogenic influence.
There is a desire to monitor changes in rangelands through time and across large geographic areas. Monitoring of rangelands, however, is complicated by the high degree of spatial and temporal variation in vegetation and soil. To provide meaningful information about rangelands involves an evaluation across large landscapes and over extended periods of time. Moreover, semi-arid and arid rangelands are significantly influenced by the quantity and timing of precipitation, creating significant inter-annual variation. Evaluating rangelands and their response to specific management (e.g., grazing) can therefore be difficult. Current field-based methods used to assess and monitor rangelands are limited in their ability to account for spatial and temporal variation. For example, traditional field-based monitoring is usually insufficient to accurately assess ecological status or to detect important changes across large geographic areas outside of the plot extent. Increasing the number of traditional ground-based monitoring plots across large spatial and temporal scales is often prohibitively expensive and still has limited evaluative capabilities.
The inadequacies of traditional ground-based sampling for rangeland assessment could be one reason that the largest rangeland management entity in the United States, the United State Department of Interior-Bureau of Land Management (USDI-BLM), has only inventoried an average of 0.6% of its national land holdings annually (˜113 million hectares) from 1998-2007, resulting in 5.4% being inventoried over this time period. Often, land-use plans are renewed without formal assessment of rangelands, as required by the National Environmental Protection Act (NEPA). Most grazing allotment renewals in the past few decades have been completed via a “grazing rider” attached to the Department of Interior's Appropriation Bill. This renewal process keeps in place the terms and conditions of previous allotment management plans without assessing whether “Standards and Guidelines” of rangeland health are satisfied. This lack of feedback limits the ability of land managers to improve knowledge of the systems' ecology and to respond adaptively.
The present application relates to one or more of the above issues.